Photogrammetry vs 3D scanning for creating a 3D model
Photogrammetry against laser scanners, structured light and handheld scanners: accuracy, range, speed, colour, cost and the surfaces each struggles with, so you pick the right one for the model you need.
Published · 10 min read · By Malya, the makers of Clarity
Both make a 3D model of a real thing, and the words are used interchangeably in product listings. They are different instruments with different strengths, and the choice between them is nearly always decided by three questions: how far away is the thing, how fine does the answer need to be, and what is its surface like. This page answers those for each.
What a scanner does differently
A 3D scanner measures distance directly. A laser scanner times a pulse of light out and back; a structured light scanner projects a known pattern of stripes or dots and watches how a surface bends it; a laser triangulation scanner sweeps a line of laser light and sees where it falls from an offset camera. Each returns a point at a known distance along a known direction, and the point is measured at the moment of capture: there is nothing to process except putting the points together.
Photogrammetry measures nothing at capture. It records photographs, and the measurement happens afterwards, in software, from the way the same points shift between pictures. That makes it cheaper (a camera), more flexible (any distance, any size of subject) and richer (every point in colour), and it makes it dependent on the subject having something to match: texture, stillness and even light.
- A scanner needs
- Line of sight and a surface that returns its light; nothing from the subject's appearance
- Photogrammetry needs
- Texture, stillness, even light, overlap, and something to set the scale
- A scanner gives
- Geometry at the instrument's accuracy, in the field, with intensity and sometimes colour
- Photogrammetry gives
- Geometry at the pixel's accuracy, after processing, always in colour
The kinds of scanner
- Structured lightA projector throws a pattern on the object and a camera reads its distortion. Desk-sized objects at tens of micrometres: parts, castings, dental and medical work, quality inspection.0.1–2 m · 20 µm–0.3 mm
- Handheld laser (triangulation)A laser line swept by hand over the object, watched by an offset camera, with tracking from targets or features. Parts to car bodies; fast, and tolerant of movement.0.2–4 m · 0.05–0.5 mm
- Terrestrial laser scannerOn a tripod, sweeping a full sphere by time of flight or phase shift: millions of points in under a minute to hundreds of metres, at a few millimetres. Buildings, plants, tunnels, quarry faces.1–1,000 m · 1–6 mm
- Handheld and mobile SLAM scannersA spinning LiDAR carried through a space, positioning itself from what it sees. A floor of a building in a walk; centimetre-level, no GNSS needed.to 120–300 m · 5–15 mm
Drone LiDAR is the airborne member of the family, and has its own page against photogrammetry: LiDAR vs photogrammetry. For how all of these work inside, the laser scanners page.
Range against accuracy
- Structured light: Desk-sized objects, sub-millimetre, 20 µm–0.3 mm
- Handheld laser scanner: Parts, castings, people, 50 µm–0.5 mm
- Close-range photogrammetry: Objects to building faces, with scale bars, 0.2 mm–5 mm
- Terrestrial laser scanner: Buildings, plants, tunnels, from a tripod, 1 mm–6 mm
- Handheld SLAM scanner: Walked through a building or a site, 5 mm–2 cm
- Drone photogrammetry: Sites and corridors, in colour, 1 cm–6 cm
- Drone LiDAR: Sites under vegetation, bare earth, 2 cm–6 cm
- Crewed aircraft: Camera or LiDAR; whole towns and counties, 5 cm–30 cm
- Satellite stereo: Regions; a few metres, 50 cm–3 m
Read the chart left to right and the methods tile it: structured light and handheld scanners for things you can pick up, close-range photogrammetry overlapping them and reaching out to building faces, the terrestrial scanner from a metre to several hundred, SLAM for walking through, the drone methods from 30 m up, aircraft and satellites beyond. Where two boxes overlap is where the choice is real; elsewhere the distance has already decided.
Head to head
| Photogrammetry | 3D scanning | |
|---|---|---|
| Accuracy at arm's length | 0.1–1 mm with scale bars and care | 0.02–0.3 mm (structured light, handheld laser) |
| Accuracy at a building | Centimetres from the air; millimetres from the ground with targets | 1–6 mm (terrestrial scanner); 5–15 mm (handheld SLAM) |
| Colour | Always, at full photographic quality | Intensity; colour from an attached camera, lower quality |
| Speed in the field | Minutes to photograph an object; a drone covers hectares an hour | A handheld scan in seconds to minutes; a tripod scan under a minute per station |
| Result available | After processing: minutes to hours | At once, in the field |
| Cost of the instrument | A camera: hundreds to a few thousand | Thousands (handheld) to tens of thousands (terrestrial) |
| Subject size | Anything, from a coin to a county | Each scanner has a working range; several kinds to cover the same span |
| Blank, shiny, dark or clear surfaces | Fail: nothing to match | Shiny and dark usually fine; glass and mirrors fail for both |
| Moving subjects, people | Fail unless perfectly still | Fine with a handheld scanner |
Surfaces, light and movement
The practical deciding factor for an object is its surface. Photogrammetry matches texture, so a machined aluminium part, a black rubber hose, a plain white wall or a window gives it nothing to match and the model comes out with holes or lumps. The classic workarounds, a matte spray or stuck-on targets, work but alter the object. A scanner does not care what the surface looks like, only that it reflects the instrument’s light back, so the same part scans cleanly; only glass, mirrors and very dark matte surfaces defeat it.
Choose photogrammetry when
- Colour and realistic texture matter: heritage, film, games, real estate, a record of how something looked
- The subject is large or far away: a site, a quarry, a building from the air
- The budget is a camera, or the drone is already flying
- The subject is still and has texture
Choose a scanner when
- Millimetres or better are the point: inspection, reverse engineering, fitting a part
- The surface is blank, shiny or dark
- The subject moves, or is a person
- You need the model in the field, now, with no processing
Which to use
| The job | Use | Because | |
|---|---|---|---|
| A casting or a machined part for inspection | Structured light or handheld laser | Tens of micrometres, and the surface is probably shiny | |
| A sculpture, an artefact, a prop for a film | Photogrammetry, or scanner plus photographs | Colour and texture are the deliverable | |
| A building's interior for a BIM model | Terrestrial or handheld SLAM scanner | Millimetres on plain walls, which photographs cannot match | |
| A site, a quarry, a stockpile yard | Drone photogrammetry | Hectares at centimetres, in colour, with the orthomosaic as the record | |
| A quarry face or a rock slope | Terrestrial scanner, or ground photogrammetry | The face is vertical; both work from the ground, the scanner more precisely | |
| A person, for a figure or a fitting | Handheld scanner | Nobody stands still for 80 photographs |
Sources
Questions people ask
Is photogrammetry a type of 3D scanning?
In everyday use, yes: both turn a real thing into a 3D model. Strictly, a scanner measures distance directly with a laser or a projected pattern, and photogrammetry infers it from photographs. The distinction matters when you need to know where the accuracy comes from and what can go wrong.
Which is more accurate for a 3D model, a scanner or photogrammetry?
For an object within arm's reach, a structured-light or handheld laser scanner: tens of micrometres against a fraction of a millimetre for careful close-range photogrammetry. For a building or a site, a terrestrial laser scanner at a few millimetres, against photogrammetry's centimetres from the air. Photogrammetry wins on colour and on cost, not on precision.
Which is faster?
Scanning gives a model in the field, in minutes, with no processing wait. Photogrammetry takes minutes to capture and hours to process, but covers far more ground per hour of capture from a drone than any scanner, and needs no one to carry an instrument round the site.
What does photogrammetry struggle with that a scanner does not?
Surfaces without texture: shiny metal, glass, dark rubber, plain white walls, water. A scanner measures them as long as they return its light (glass and mirrors defeat it too). Moving subjects, including people, which a handheld scanner captures in seconds and a camera cannot hold still for.
See it on a real site.
Explore is free, with no card and no expiry: a real quarry, already flown and processed, with every measuring tool on it.
Read next
- How accurate is photogrammetry? Real figures and what decides themThe centimetres, where they come from, and how to make a survey hit a tolerance rather than hope to.
- LiDAR vs photogrammetry: which is better for a survey?Laser against camera: what each sees through trees, what each costs, and the cases where one wins outright.
- The disadvantages of photogrammetry: where it fails, and whyVegetation, water, glass, doming, rolling shutter, moving things: every failure, with its cause and its fix.
- All resources